Systems and methods for fabricating dental appliances or shells

ABSTRACT

Systems and methods are disclosed for cutting and trimming dental molds and oral appliances by receiving a digital model of teeth, determining a cutting loop path and applying a drape wall to the cutting loop to generate a simplified tooth base in a dental mold having an inner arch curve and an outer arch curve. The oral appliance may be formed on the dental mold and a cutter may be applied using a sweeping motion across the inner and outer arch curves.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/423,840 filed May 28, 2019, which is a continuation of U.S. patentapplication Ser. No. 15/230,251 filed Aug. 5, 2016 (now U.S. Pat. No.10,357,336), which claims the benefit of priority to U.S. Prov. App. No.62/238,539 filed Oct. 7, 2015, each of which is incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates to methods and apparatus for fabricatingdental appliances. More particularly, the present invention relates tomethods and apparatus for forming and cutting of molds used infabricating oral appliances in an automated process and with a singlemachine.

BACKGROUND OF THE INVENTION

Conventionally, braces use brackets connected by wires to encourageteeth to move but more people are having success with clear orthodonticdevices called aligners which are a series of tight-fitting custom-maderetainers that slip over the teeth. Once a dentist or orthodontistdecides how to correct a patient's bite, they make a plan for movingteeth. Patients are then fitted for several versions that make slightadjustments to move the teeth over the treatment time. Aligners madefrom a clear plastic or acrylic material and fit tightly over the teeth,but can be removed for eating, brushing, and flossing. Patients wear anew aligner every few weeks to continue moving the teeth into thedesired position.

Treatment time with invisible teeth aligners is based on how much theteeth need to be moved or rotated. The more the patient bite is off orthe more crooked the teeth, the longer it will take. Treatment usuallytakes between 10 and 24 months. An adult who had braces as a child mayneed teeth aligners for as little as 10 weeks.

Conventional aligners are typically fabricated at a central lab remotefrom the dental offices and such systems cause delays and fail to offerreal-time, instant treatment for patients. Moreover, the manufacturingof the aligners are time-consuming and require multiple steps infabricating the molds used to create the aligners as well as thealigners themselves.

Therefore, there remains a need for cost-effective systems which enablethe modeling and fabrication of the molds and aligners directly at thedental office locations for providing real-time, instant treatment.

SUMMARY OF THE INVENTION

Systems and methods are disclosed for cutting and trimming dental moldsand oral appliances by receiving a digital model of teeth, determining acutting loop path and applying a drape wall to the cutting loop togenerate a simplified tooth base in a dental mold having an inner archcurve and an outer arch curve. The oral appliance may be formed on thedental mold and a cutter may be applied using a single sweeping motionacross the inner and outer arch curves.

The system enables an easy way to cut and trim tooth models. The systemallows close control by the treating professional at each stage byallowing specific movements from one stage to the next stage. The systemcan form aligners quickly and efficiently due to the drape wallsimplification. The CNC machines can manufacture each shell as a customdevice for many stages of tooth movement. The mold can be cut/trimmedusing inexpensive 2D cutting machines, if needed. Additionally, theresulting oral appliances (aligners, shells, etc.) can be removed fromthe positive mold with minimal force, reducing risk of shell tear fromexcessive removal force.

Generally, one embodiment for a method of forming an oral appliance maycomprise receiving a digital model of a patient's dentition, calculatinga rule-based cutting loop path on the model for determining a path fortrimming a mold replicating the patient's dentition, applying a drapewall from the cutting loop on the model to reduce a complexity of themodel, determining a position of a cutting instrument relative to themold for trimming the mold, generating a computer numerical control codebased on the drape wall and position of the cutting instrument, andfabricating the mold based on the generated computer numerical controlcode.

Another embodiment for a method of forming an oral appliance maygenerally comprise receiving a digital model of a patient's dentition,calculating a rule-based cutting loop path on the model for determininga path for trimming a mold replicating the patient's dentition, applyinga drape wall from the cutting loop on the model to reduce a complexityof the model, determining a predetermined height of a base of the model,generating a computer numerical control code of the model, andfabricating the mold based on the generated computer numerical controlcode.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description of the figures of specific embodiments of theinvention is merely exemplary in nature and is not intended to limit thepresent teachings, their application or uses. Throughout the drawings,corresponding reference numerals indicate like or corresponding partsand features.

FIG. 1 shows an exemplary process for fabricating an oral appliance.

FIGS. 2 and 3 show side views of an exemplary process of defining a trimline between opposed dots on a digital model of the oral appliance.

FIG. 4 shows a top view of an oral appliance formed with one or moreslots to facilitate manufacturing.

FIG. 5 shows a side view of an oral appliance mounted on a base formanufacturing.

FIG. 6 shows a side view of the oral appliance and some of thedirections that the appliance may be translated and/or rotated tofacilitate trimming of the appliance.

FIG. 7 shows a top view of a cutting device which may be used to trimthe oral appliance and some of the directions that the cutting devicemay be articulated.

FIG. 8 shows a top view of an oral appliance and a cutting device formanufacturing.

FIG. 9 shows a side view of an oral appliance secured to a base forprocessing.

FIG. 10 shows an exemplary process for laser cutting a physical mold forthe oral appliance.

FIG. 11 shows a side view of an oral appliance formed with a toolingcavity to facilitate articulation of the oral appliance.

FIG. 12 shows a side view of another oral appliance having a regionformed to facilitate removal of the appliance via a stream of air orgas.

FIG. 13 shows an exemplary process for facilitating removal of the oralappliance.

FIG. 14 shows a side view of another oral appliance having a cavityformed to facilitate its removal via a wedged removal member.

FIG. 15 shows an exemplary process for facilitating removal of the oralappliance via the wedged removal member.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described with respect to particularembodiments but the invention is not limited thereto but only by theclaims. Any reference signs in the claims shall not be construed aslimiting the scope thereof.

As used herein, the singular forms “a”, “an”, and “the” include bothsingular and plural referents unless the context clearly dictatesotherwise.

The terms “comprising”, “comprises” and “comprised of” as used hereinare synonymous with “including”, “includes” or “containing”, “contains”,and are inclusive or open-ended and do not exclude additional,non-recited members, elements or method steps. The terms “comprising”,“comprises” and “comprised of” when referring to recited members,elements or method steps also include embodiments which “consist of”said recited members, elements or method steps.

Furthermore, the terms first, second, third and the like in thedescription and in the claims, are used for distinguishing betweensimilar elements and not necessarily for describing a sequential orchronological order, unless specified. It is to be understood that theterms so used are interchangeable under appropriate circumstances andthat the embodiments of the invention described herein are capable ofoperation in other sequences than described or illustrated herein.

The term “about” as used herein when referring to a measurable valuesuch as a parameter, an amount, a temporal duration, and the like, ismeant to encompass variations of +/−10% or less, preferably +/−5% orless, more preferably +/−1% or less, and still more preferably +/−0.1%or less of and from the specified value, insofar such variations areappropriate to perform in the disclosed invention. It is to beunderstood that the value to which the modifier “about” refers is itselfalso specifically, and preferably, disclosed.

The recitation of numerical ranges by endpoints includes all numbers andfractions subsumed within the respective ranges, as well as the recitedendpoints.

All documents cited in the present specification are hereby incorporatedby reference in their entirety.

Unless otherwise defined, all terms used in disclosing the invention,including technical and scientific terms, have the meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. By means of further guidance, definitions for the terms used inthe description are included to better appreciate the teaching of thepresent invention. The terms or definitions used herein are providedsolely to aid in the understanding of the invention.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment of the present invention. Thus, appearances of the phrases“in one embodiment” or “in an embodiment” in various places throughoutthis specification are not necessarily all referring to the sameembodiment, but may. Furthermore, the particular features, structures orcharacteristics may be combined in any suitable manner, as would beapparent to a person skilled in the art from this disclosure, in one ormore embodiments. Furthermore, while some embodiments described hereininclude some but not other features included in other embodiments,combinations of features of different embodiments are meant to be withinthe scope of the invention, and form different embodiments, as would beunderstood by those in the art. For example, in the following claims,any of the claimed embodiments can be used in any combination.

In fabricating oral or dental appliances which are used to treatmalocclusions in a patient's dentition, the oral appliance may beinitially formed via, e.g., thermal forming or three-dimensional (3D)printing techniques. Once formed, the oral appliance may require furtherprocessing to trim excess material for ensuring a good fit on thepatient. However, trimming this excess is typically a time-consumingprocess which requires a separate step after forming the appliance.

In one embodiment, the forming and cutting of the oral appliance may beaccomplished in an automated process and with a single machine.Generally, a patient's scanned dentition may be used to create one ormore molds of the dentition where each subsequent mold is configured tosubsequently follow a corrective path for one or more teeth forcorrecting malocclusions in the dentition. Each of the one or more moldsmay be used as a mold for thermal forming or 3D printing a correspondingoral appliance upon the molds. The resulting oral appliances may be usedin sequence to move the dentition for correcting the malocclusions.

FIG. 1 shows an exemplary process for utilizing computerized or computernumerical control (CNC) for fabricating the oral appliances. Typical CNCsystems and end-to-end component design is highly automated usingcomputer-aided design (CAD) and computer-aided manufacturing (CAM)dental software. The process begins by loading digital models of thelower and upper arches 10 of the subject's dentition into a computersystem having a processor. This may involve capturing the 3Drepresentation of the surfaces, e.g. external contours, of a patient'sdentition for correcting one or more malocclusions. For this purpose,the subject may be scanned using a 3D scanner, e.g. a hand-held laserscanner, and the collected data can then be used to construct a digital,three dimensional model of the body part of the subject. Alternatively,the patient-specific images can be provided by a technician or medicalpractitioner by scanning the subject or part thereof. Such images canthen be used as or converted into a three-dimensional representation ofthe subject, or part thereof.

With the digital model of the subject's dentition loaded into thecomputer system, the process then calculates a rule-based cutting looppath 12 on the digital model for determining a path along which the CNCmachine may follow for trimming the mold upon which the oral applianceis fabricated. Once the cutting loop path has been determined, theprocess may then reduce the model complexity by applying a drape wall 14(as described in further detail below) which digitally extends from thecutting loop path towards a bottom of the mold model (e.g., away fromthe portion of the appliance which contacts the teeth and towards theportion of the appliance which extends towards the gums). The drape wallfunctions by defining a region of the oral appliance which can beignored since this portion is to be removed or trimmed.

The digital model may then be rotated around its center in relation to areference plane in order to calculate a cutting blade tilt angle andblade height 16 (relative to the reference plane) which may be appliedduring the actual trimming procedure. With this information, the code tobe sent to the CNC machine may be generated based on the stageconfiguration to be utilized 18. A physical mold base to be used in theprocessing procedure may be trimmed and one or more anchoring featuresmay be incorporated into the mold base for securing a holding jig whichmay be used to secure the oral appliance 20 to the mold base. Thecompleted digital model may then be exported as, e.g., a 3D printeracceptable model 22, for printing the oral appliance or mold upon whichan oral appliance may be formed.

FIGS. 2 and 3 show side views of a portion of a digital model of apatient's dentition showing a tooth 30 and gums 32, as an example. Incalculating a rule-based cutting loop path 12, as shown in FIG. 1 above,the scanned image of the patient's dentition may be processed toidentify the interface areas between the teeth and gums 32. One or moremarkers 34, 36 may be digitally placed on the model at these interfaceregions such that the markers 34, 36 are opposed to one another on themodel. A boundary or trim line 42 may then be defined to extend betweenthe markers 34, 36 such that the trim line 42 follows the border betweenthe teeth and gums. With the trim line 42 identified on the model, aseries of drop lines 38, 40 which are parallel to one another and spacedapart, e.g., uniformly, relative to one another may be formed to beginfrom the trim line 42 and extend away from the trim line 42 and awayfrom the dentition in a straight path. This base region 44 formed by thedrop lines 38, 40 below the trim line 42, i.e., away from or opposite tothe dentition, may be identified and demarcated as a region to beremoved from the mold.

To ensure that the height of the mold including the base region 44 doesnot excessively stretch the material forming the oral appliance, thesystem may be used to determine the lowest point (relative to the trimline 42 and appliance 30) for trimming the entire mold just above thisidentified lowest point. In one embodiment, the trimming may be donewith a predetermined margin, e.g., 2 mm, above the lowest identifiedpoint. The base region wall can also be tapered slightly based on theheight of the base region wall so that the width of the base region 44tapers from a larger width adjacent to the trim line 42 down to arelatively smaller width away from the trim line 42. The resulting moldformed from the dentition (or corrected dentition) is shown in the sideview of FIG. 3 where the base region 44 has a minimum height of thepredetermined margin, e.g., 2 mm.

Once the mold has been formed with the base region 44, the mold may befurther processed. A bottom view of a formed mold 50 is shown in FIG. 4with slots 52, 54 formed into a surface 56 of the mold 50 into whichtools or anchors can be inserted for securing the mold 50 in placeduring further processing procedures. FIG. 5, for example, shows a sideview of the fabricated mold 50 secured along its interface surface 56and anchored via slots 52, 54 to a surface 62 of a platform 60. FIG. 6shows one configuration where the platform 60 holding the physical mold50 for pressure-forming the oral aligner may be positioned upside down,i.e., such that the mold 50 is held in an inverted position as shown.The platform 60 may be fixed or secured upon a stage 68 which may beactuated to move the platform 60 and mold 50 in a vertical direction 64(up/down) or linearly 66 within a plane defined by the stage 68 andplatform 60, as shown in FIG. 6, to facilitate cutting or trimmingprocesses for the mold 50. The stage 68 may also be actuated to rotate70 the platform 60 and mold 50 within the plane defined by the stage 68such that the stage 68 rotates about an axis which may be aligned to becollinear with a central axis 72 of the mold 50, as shown in FIG. 7.

Another configuration may position the stage 68 relative to a bladewhich may be translated and/or rotated relative to mold 50 and stage 68.The system may calculate each motion stage parameters and while the mold50 is moved rotationally, the blade may be used to cut or trim the mold50, as needed. This may involve rotating the model 50 around its centerand calculating the blade tilt angle and blade height 16, as describedabove.

Yet another configuration may involve moving the stage 68 and mold 50relative to a stationary blade such that the mold 50 is rotated, tilted,and/or translated by the stage 68 while the position of the bladeremains unchanged. The system then adjusts different tools to trim themold 50 at the pre-designated cutting path. In this or any othervariation, the blade can include a mechanical blade or a laser cuttingtool and software may be used to calculate the laser focus to easiermove the source back and force or attenuate its power to focus and cutthe mold 50 at designated locations.

In one implementation for processing the mold, FIG. 8 shows a top viewof a mold 50 positioned upon a stage and rotated relative to astationary cutting blade 80. The mold 50 may be secured to theunderlying platform and stage and rotated within the plane of theplatform in the direction 70 about its central axis 72 which may becoincident with the axis of rotation defined by the stage. The cuttingblade 80 having a cutting edge 82 may be positioned relative to the moldat the predetermined height and angle relative to the mold 50, asdescribed herein, to trim the mold 50 as it rotates.

In this variation, instead of generating a complex 3D cutting curve, thesystem simply uses a 2D flat curve by optionally setting a water markcutting plane. The advantage is that no numerical controller is neededto cut the molds. Instead, the mold 50 can be simply placed by hand androtated (e.g., manually or automatically), as shown, to push it throughor past the cutting blade 80. The action may be similar to cutting awood board with a circular motion rather than a straight or linearmotion.

Another advantage of this configuration is the ability to utilize aseparate fixture which can be used to sandwich the material forming theoral appliance after placement upon the mold, e.g., when thermal formingthe oral appliance. The material from which the oral appliance isthermal formed, if used for fabrication, may be secured directlyremoving the need for yet another fixture on the mold itself. Oneimplementation uses a two-dimensional (2D) laser cutting tool that canbe used to cut along a flat curve formed by a horizontal silhouette linegenerated by a projection to the base surface.

FIG. 9 shows a side view of one embodiment where the mold 50 ispositioned above a platform 60 with the plastic shell mold 92 afterthermal forming upon the mold 50. The entire assembly of the mold 50,platform 60, and shell mold 92 rests on a flat bottom fixture base 90having a clamping fixture with one or more clamping plates 94, 96 oneither side to secure the mold 50 and shell mold 92. The fixtureassembly may be used to secure the shell mold 92 for further processingsuch as trimming. Once the processing has been completed, the clampingplates 94, 96 may be released and the shell mold 92 and/or mold 50 maybe removed from the fixture base 90.

In the event that the physical mold is processed by laser cutting, thesteps shown in the flow diagram of FIG. 10 may be implemented in anotherembodiment. Initially, a digital model of the lower and upper arches maybe loaded in the system 100, as described previously. The system maythen calculate a rule based cutting loop path for the 2D cutting system102, as discussed above. Model complexity may be reduced by applying thedrape wall from the cutting loop 104, as also discussed above. Theprocess trims the mold base above a water mark 106 which may beimprinted upon the mold to demarcate a boundary. For laser cutters, thesystem may generate a 2D laser cutting path using vertical projects 108and determine the border of the shadow as the cutting path 110. Thesystem may then export the 3D printer model 112 for fabrication. Theprocess may be repeated for each subsequent mold used for fabricatingone or more of the corresponding oral appliances.

Regardless of how the mold is trimmed or how the oral appliance isprocessed upon the mold, the separation and release of the shell(aligner or oral appliance) from the mold can be generally difficult dueto the lack of any features for grabbing the mold. To address this, oneor more holes or cavities 122 may be drilled or otherwise defined atvarious locations within the mold 120 and optionally at an angle 126relative to a normal direction of the mold, as shown in the end view ofFIG. 11. The angling of the hole or cavity 122 enables the insertion ofa tool 124 which may be positioned within to provide a counterforce forreleasing and removing an oral appliance 128 formed upon the mold 120.

Another embodiment shown in the end view of FIG. 12 which illustrates anend view of a mold 130 formed to have a hole or cavity 132 which extendsthrough the bottom of the mold 130 and into proximity of the top of themold, i.e., where the model of the patient's dentition is located. Athin layer 134 of the mold may extend over the hole 132 to provide asurface upon which the oral appliance 128 may be fabricated, asdescribed herein. However, once fabrication of the oral appliance 128has been completed and trimmed suitably, the tip 138 of a tool 136appropriately sized may be inserted into the opening 132 and pushedthrough the thin layer 134 of the mold 130 and into contact against aninner surface of the oral appliance such that the oral appliance 128 maybe urged to release from the mold 130. Alternatively, the tool 136 maycomprise an air blower so that the tip 138 may be positioned within theopening 132 into proximity of the layer 134, as shown by the detail viewD, where a jet of air introduced through tip 138 may be break throughthe layer 134 and urge the oral appliance 128 to release from the mold130.

To ensure that the mold 130 retains its strength during fabrication ofthe mold, oral appliance, or release of the oral appliance from themold, the mold 130 may be optionally fabricated to include a honeycomb,mesh, or other porous feature underlying the surface of the mold 130.With the added structural strength provided by a honeycomb or mesh, thelayer 134 may be broken or punctured and still allow of the passage ofthe air but the mold 130 may have the structural resilience to withstandthe pressures generated by the shell formation upon the mold 130surface.

FIG. 13 illustrates a flow diagram for removing the oral appliancefabricated upon a mold, as described above. As previously described, thedigital model of the lower and upper arches may be loaded into thecomputer system 140. The system may then identify an appropriate areaalong the model for tool insertion 142. Such an area may be located awayfrom the dentition model and so as not to interfere with the fabricationof the oral appliance upon the mold. The system may trim the model bydefining a through-hole from insertion 144 and to strengthen thethrough-hole, the system may then remodel the hole area by forming theregion of the hole adjacent to where the dentition is modeled as a meshor honeycomb configuration 146 to provide strength to the model whenfabricated but which still allows for air to pass through the openingsdefined by the mesh or honeycomb. The model may incorporate a receivingfixture to allow for the insertion of tools and/or allows for thesecurement of the mold during removal of the oral appliance from themold 148. Once the model has been completed, a 3D printer acceptablemodel may be exported 150.

FIG. 14 shows yet another exemplary embodiment for facilitating removalof the fabricated oral appliance from the mold in the end view of mold160. The mold 160 may be formed to define an opening or channel 162which extends through the mold 160 from a bottom (e.g., opposite to theportion of the mold replicating the dentition) towards a top (e.g.,portion of the mold replicating the dentition such as the occlusalsurfaces). In this embodiment, a tapered structure 164 may be formed tobe part of the oral appliance 172 which is formed upon the mold 160. Thetapered structure 164 may remain attached to an internal surface of theoral appliance while being formed with a tapered surface 166 whichtapers to a larger diameter structure within the opening or channel 162away from the oral appliance 172.

The tapered structure 164, once formed, may present a cork-likestructure which helps to secure the oral appliance upon the mold 160during fabrication and processing. Once the oral appliance 172 iscompleted and ready for release and removal from the mold 160, a toolmay be inserted into the opening or channel 162, in the direction 170 asindicated, and used to gently push against the bottom surface of thetapered structure 164 to urge the release of the oral appliance 172 fromthe mold 160 until the tapered structure 164 is removed entirely fromthe opening or channel 162, in the direction 168 as indicated. Once theoral appliance 172 has been removed entirely, the tapered structure 164may be removed from the oral appliance 172 as well.

FIG. 15 illustrates a flow diagram for removing the oral appliancefabricated upon a mold using the tapered structure 164, as describedabove. As previously described, the digital model of the lower and upperarches may be loaded into the computer system 180. The system may thenidentify an appropriate area along the model for tool insertion 182.Such an area may be located away from the dentition model and so as notto interfere with the fabrication of the oral appliance upon the mold.The system may trim the model by defining a through-hole from insertion184 and to strengthen the through-hole, the system may then remodel thehole area by forming or inserting the tapered structure 164 (e.g.,reverse cork-type structure) 186. The model may incorporate a receivingfixture to allow for the insertion of tools and/or allows for thesecurement of the mold during removal 188 of the oral appliance from themold. Once the model has been completed, a 3D printer acceptable modelmay be exported 190.

The system or method described herein may be deployed in part or inwhole through a computer system or machine having one or more processorsthat execute software programs with the methods as described herein. Thesoftware programs may be executed on computer systems such as a server,domain server, Internet server, intranet server, and other variants suchas secondary server, host server, distributed server, or other suchcomputer or networking hardware on a processor. The processor may be apart of a server, client, network infrastructure, mobile computingplatform, stationary computing platform, or other computing platform.The processor may be any kind of computational or processing devicecapable of executing program instructions, codes, binary instructions orthe like that may directly or indirectly facilitate execution of programcode or program instructions stored thereon. In addition, other devicesrequired for execution of methods as described in this application maybe considered as a part of the infrastructure associated with thecomputer system or server.

The system or method described herein may be deployed in part or inwhole through network infrastructures. The network infrastructure mayinclude elements such as computing devices, servers, routers, hubs,firewalls, clients, wireless communication devices, personal computers,communication devices, routing devices, and other active and passivedevices, modules or components as known in the art. The computing ornon-computing device(s) associated with the network infrastructure mayinclude, apart from other components, a storage medium such as flashmemory, buffer, stack, RAM, ROM, or the like. The processes, methods,program codes, and instructions described herein and elsewhere may beexecuted by the one or more network infrastructural elements.

The elements described and depicted herein, including flow charts,sequence diagrams, and other diagrams throughout the figures, implylogical boundaries between the elements. However, according to softwareor hardware engineering practices, the depicted elements and thefunctions thereof may be implemented on machines through the computerexecutable media having a processor capable of executing programinstructions stored thereon and all such implementations may be withinthe scope of this document. Thus, while the foregoing drawings anddescriptions set forth functional aspects of the disclosed methods, noparticular arrangement of software for implementing these functionalaspects should be inferred from these descriptions unless explicitlystated or otherwise clear from the context. Similarly, it will beappreciated that the various steps identified and described above may bevaried, and that the order of steps may be adapted to particularapplications of the techniques disclosed herein. All such variations andmodifications are intended to fall within the scope of this document. Assuch, the depiction or description of an order for various steps shouldnot be understood to require a particular order of execution for thosesteps, unless required by a particular application, or explicitly statedor otherwise clear from the context.

Thus, in one aspect, each method described above and combinationsthereof may be embodied in computer executable code that, when executingon one or more computing devices, performs the steps thereof. In anotheraspect, the methods may be embodied in systems that perform the stepsthereof, and may be distributed across devices in a number of ways, orall of the functionality may be integrated into a dedicated, standalonedevice, or other hardware. All such permutations and combinations areintended to fall within the scope of the present disclosure.

The applications of the devices and methods discussed above are notlimited to the dental applications but may include any number of furthertreatment applications. Moreover, such devices and methods may beapplied to other treatment sites within the body. Modification of theabove-described assemblies and methods for carrying out the invention,combinations between different variations as practicable, and variationsof aspects of the invention that are obvious to those of skill in theart are intended to be within the scope of the claims.

What is claimed is:
 1. A method of forming an oral appliance,comprising: receiving a digital model of a patient's dentition;calculating a rule-based cutting loop path on the model for determininga path for trimming a mold replicating the patient's dentition; applyinga drape wall from the cutting loop on the model to reduce a complexityof the model; determining a position of a cutting instrument relative tothe mold for trimming the mold; generating a computer numerical controlcode based on the drape wall and position of the cutting instrument; andfabricating the mold based on the generated computer numerical controlcode.